The present invention concerns shaped metallic products such as steel pipe, tube or conduit made in a continuous manufacturing process that, along with forming the metallic shaped product, adds color to the outer surface of the product. Metallic products such as tubes, pipes and conduit containing the appearance of color are extremely useful. Colored tubes may be used to designate the purpose of the tube. For example, red-colored tube can be used to contain the electrical wires for fire detection and response systems; blue-colored tube can be used to contain drinking water or coolant; yellow-colored tube can be used to contain and transport hot water. The addition of color to tube assists in installation and inspection of the tube and aids in easy identification of tube that is used for a particular purpose.
Previously, manufacture of colored tube generally involved a non-continuous process. In previous processes, metal strip was formed into tube in one process and then removed from the forming process. Color was then added to the tube in a different process. The coloration process occurred at a separate location and a separate time from the tube manufacturing process. The process for making the tube and the process for adding coloration, in the previous processes, were not part of the same continuous process. The use of separate processes for making and adding color to tube has the drawbacks of decreasing the efficiency and increasing the cost of the process of creating colored tube, and preventing the colorant from being added to the tube as part of the tube manufacturing process
In the current invention, the addition of color to the tube, pipe or conduit occurs in the same continuous process as that in which the tube, pipe or conduit is formed. The coloration process is part of the continuous manufacturing process. The tube, pipe or conduit does not cease moving and is not cut until after the coloration process in the current invention. It is understood that while the word “tube” is frequently used in this description, the description applies equally to pipe, conduit and other metallic cylinders and columns as well as tube. In addition, while the specific examples mentioned in the preferred embodiments frequently refer to tube, the present invention includes pipe, conduit, columns, cylinders, squares, rectangles, solids and non-solid shapes (such as bars, beams, strips or other non-solid shapes) as well as tube.
The current invention has many benefits, including increased efficiency, decreased need for space for equipment, decreased labor and decreased difficulties involved in transferring formed and cut tube to a coloration station. The current invention provides for clearly visible tube systems, eases and saves time with installation and inspection, and assists with future upgrades and maintenance of tube systems. The current invention decreases the labor and material costs associated with painting and creates greater system integrity.